A series of renderings reveals how a shifting corona might form the beginning of a black hole X-ray flare. Photo by NASA/JPL-Caltech
PASADENA, Calif., Oct. 28 (UPI) -- Scientists now have a better understanding of how black holes come to launch flares, thanks to the observational skills of two NASA Explorer missions -- Swift and the Nuclear Spectroscopic Telescope Array, or NuSTAR.
A black hole flare is an expelled beam of X-rays. For the first time, scientists have linked this phenomenon with the excitement of a black hole's corona. Swift and NuSTAR witnessed a black hole flare as the corona's excited material suddenly launched away from its host.
The discovery "will help us understand how supermassive black holes power some of the brightest objects in the universe," Dan Wilkins, a scientist at Saint Mary's University in Halifax, Canada, said in a press release.
Black holes host two main sources of light. They themselves don't emit radiation, but as matter gets sucked into their accretion disk, particles are excited by heat and pressure and give off a variety of light waves. The second and less understood source is the corona.
The corona is an organization of high-energy particles that surround a black hole and give off X-rays. But scientists aren't exactly sure what they are or how they're organized.
Some suggest the corona is shaped like a lamppost, with light bulb-like concentrations of energy situated above and below the black hole along its rotational axis. Another theory posits that the corona is more broadly scattered around the black hole, or layered like a sandwich -- slices of energized particles, the black hole the meat and cheese in between.
The latest research suggests the lamppost theory is most accurate.
Swift and NuSTAR enabled scientist to see a sudden shift in the corona of Markarian 335, or Mrk 335, a black hole situated 324 million light-years away in the vicinity of the constellation Pegasus.
The X-ray telescopes witnessed a change in brightness, signalling a movement of the corona. The data suggests the corona lurched quickly outward at 20 percent of the speed of light. Researchers believe they witnessed the ejection and eventual collapse of the corona, a phenomenon that may yield the formation of flares.
"The corona gathered inward at first and then launched upwards like a jet," Wilkins said. "We still don't know how jets in black holes form, but it's an exciting possibility that this black hole's corona was beginning to form the base of a jet before it collapsed."
A new paper on the discovery was published this week in the Monthly Notices of the Royal Astronomical Society.
